1. Field of the Invention
Three-dimensional, autostereographic prints with lenticular surfaces are described. Reflective backside coating compositions and processes essential to the manufacture of the three-dimensional prints are also described.
2. Background of the Art
Stereo-optical images have been available for many years. Almost all of them are based upon the same principle of displaying multiple images (i.e., at least two images) at the same time, each image displaying the same scene from a different perspective, approximating the different perspectives that would be seen by the left and right eye. Each image is then simultaneously displayed in a manner that enables each eye to view its appropriate image. With each eye receiving an image with an appropriate perspective, a scene with natural depth to it is seen.
The old `stereopticons` and modern three-dimensional viewers for children provide separate images which are viewed through separate eyepieces to provide the different perspectives. More modern three-dimensional photographic images, such as that shown in U.S. Pat. No. 3,751,258 have a lenticular surface over multiple images. The optical effect of the lenticles is to direct the transmitted optical images towards the appropriate viewing eye. U.S. Pat. No. 3,751,258 requires that a reflective backing layer be attached to the radiation-sensitive element and that the reflective backing layer be permeable to the baths or other means required to process the radiation-sensitive element to a visible image. The properties necessary in formulating a reflective backing layer with those properties has proven to be difficult to achieve in actual practice. A presently commercial embodiment of this technology has between ten and twelve layers coated onto the lenticular surface and requires two or three passes on coating apparatus to lay those layers onto the surface. That is a complex and expensive procedure.
U.S. Pat. No. 4,629,667 describes a radiation curable reflective coating composition for the backside of photographic prints. These compositions contain white pigment, crosslinkable water-soluble binder, and crosslinking agent for the binder.